Leakproof dry cell



July 13, 194s.

R. J. scHMELzER y LEAKPROOF DRY CELL- Filed Sept. 6, 1945 /Z 15ML fou.

Pefenfed July 13, i948 LEAKPROOF DRY CELL Rupert J. Schweizer, Mallieon,I Wis., assignor to Ray-O-Vac Company, a corporation of Wisconsin Application vSeptember 6, 1945,Serial No. 814,691

` l This invention relates to dry-cells and more particularly to a leak-proof jacket for a dry-cell wherein better electrical contact is maintained between the conventional metal electrode and the metal bottom closure.

In order to prevent leakage of electrolyte from a dry-cell, it is necessary to provide a special strong outer-jacket which is capable of resisting chemical attack by electrolyte and which also has suilicient mechanical strength to withstand substantial internal pressure due to gas and expanding solids. t A metal jacket insulated from both electrodes lhasbeen found successful, but in order to hold the outer dimensions of the cell to a standard size, it is necessary to make the cup shaped zinc electrode a little smaller inl diameter, to allow suloient room for the insulation and sheet metal casing. Electrically nonconductive jackets have been found satisfactory, but some difficulty is encountered in maintaining good electrical contact between the metal bottom closure and the electrode, if the cardboard jacket elongates slightly.`

The primary object of the present invention is to insure good electrical contact with the bottom closure by means of a thin metal foil lining on the cardboard jacket.

Another object of the invention is to provide an improved bottom closure which will grip tightly the outer shell and will be slightly resilient, so as to compensate fora little stretching of the outer jacket.

The invention is illustrated in a preferred embodiment in the accompanying drawing, Which- Figure 1 is a vertical sectional view of a leak- `proof dry-cell embodying the invention; Fig. 2, a fragmentary vertical sectional view of adrycell showing a modified type of bottom closure;

and Fig. 3, a fragmentary enlarged sectional view 4 Claims. (Cl. 13G-133) board on a mandrel and then cutting the tubing to a proper length. Lead foil is preferred but tin, I

aluminum, or other metal foils may be used.

A metal lbottom closure I3 forms the bottom terminal of the dry-cell and preferably has its marginal edge portions turnedl downwardly and inwardly, so as to grip opposite faces of the shell and maintain'good electrical contact with' the metal foil I2, as indicated at H. Thus it will be understood that even though the bottom of the cup shaped electrode should be displaced slightly from physical contact with the bottom closure, good electrical contact will be maintained by the metal foil. The dry-cell may -be closed by a metal closure I5, having a terminal contact i8 which embraces the carbon electrode, and the edges of the closure may bearagainst the intumed top marginal portion of the shell Il, which has been wrapped about the top of the zinc can and bent inwardly, as indicated at I1. It willbe understood that other types of top'closures may be used, but there must be no short circuit between inA the carbon electrode and the zinc electrode.

In the embodiment shown in Figure 2, the parts are identical except that a bottom closure is made of an outer disk i8 and an inner disk I9,

y whose central portion is dished inwardly so as to maintain resilient contact with the bottom of the zinc electrode`4. The marginal edge portion of the inner disk i9 is bent downwardly and inwardly, as indicated at 20, so as to grip the jacket i i. This type of bottom closure is stronger than the one shown in Figure 1, and there is even less chance of gas 'pressure causing a separation of contact between the bottom of the zinc cup and the inner'disk i9.v

-The foregoing detailed description is given for clearness of understanding only, and no unnecessary limitations should be understood therefromL showing the outer shell of non-conductive material and the lining of metal foil. l

In the embodiment illustrated, a conventional dry-cell, is shown -with a conventional cup shaped zinc electrode v4, provided with a centrally disposed carbon electrode 5 having a bobbin 6 of depolarizing material in an electrolyte paste 1. A

for some modifications will be obvious to those skilled in the art.

I claim:

1. A leak-proof dry-cell having a cup shaped metal electrode and a centrally disposed carbon electrode, comprising:` an electrically non-conductive shell lined with metal foil and having its marginal end portions turned inwardly' about said metal electrode; a metal bottom closure of less diameter than the exterior of said shell and having its marginal portions bent to grip the lower marginal end portions of said shell so as to make a liquid tight joint therewith and maintain electrical contact with the metal foil; and a top closure of less diameter than the exterior of the shell, said closure having an exposed metal tertrode. 3. A dry-cell as specined in claim i, in which the bottom closure isrormed o! two metal disks which are spaced at their central portion and one oi said disks has its marginal edge portion turned downwardly and inwardly together to grip opmite faces of the shell.

4. A dry-cell as specified in claim 1, in which the bottom closure is formed of two metal disks which I are spaced at their central portion, the outer disk being of less diameter than the inner disk and the marzinai'portion ot the inner disk being turned downwardly and inwardly so as to grip .the edge 5 portion of the outerdisk and the lower end portion ofthe shell.

RUPERT J. BCHMELZER..

mammals crrnn 1 The following references are ot record in the rile of this patent:

X UNITED STATES PATENTS Number' 4 Name Date 15l 2,379,189 RUP!) June 26, 1945 2,892,795 Anthony et al Jan. 8, 1946 

